Vitamin D: Why is it needed and where to get it?

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Vitamin D: Why is it needed and where to get it?

Section 1: The role of vitamin D in the human body

Vitamin D, despite its name, is actually a cryptormon, and not vitamin in the strict sense of the word. It plays a key role in maintaining the health of bones, the immune system, the nervous system and the general physiological function. Its influence extends much further than just maintaining strong bones.

1.1 Regulation of the metabolism of calcium and phosphorus:

The main and most famous vitamin D function is the regulation of the metabolism of calcium and phosphorus. It contributes to the absorption of calcium from the intestines, ensuring its sufficient intake in the blood. When the level of calcium in the blood falls, vitamin D stimulates the release of calcium from the bones, thus maintaining its concentration within normal. In addition, vitamin D affects the reabsorption of phosphorus in the kidneys, preventing its excessive excretion in the urine. This complex mechanism ensures the maintenance of optimal bone mineralization and prevents the development of rickets in children and osteomalization in adults.

  • The mechanism of action in the intestines: Vitamin D, in its active form (calcitriol), is associated with the vitamin D (VDR) receptor in the intestinal cells. This complex activates genes encoding proteins necessary for calcium transport through the intestinal mucosa into the bloodstream. Such proteins include Calbindin-D9K and other calcium-tracing proteins. Without enough vitamin D, calcium absorption is significantly reduced.

  • The mechanism of action in the bones: Vitamin D stimulates the activity of osteoblasts (cells that build bone tissue) and osteoclasts (cells that destroy bone tissue). Normally, these processes are balanced, ensuring constant renewal of bone tissue. However, with vitamin D deficiency, the mineralization of bone tissue is disturbed, which leads to its softening and increased fragility.

  • The mechanism of action in the kidneys: Vitamin D stimulates the reabsorption of calcium and phosphorus in the renal tubules, preventing their loss in urine. This is especially important for maintaining the normal level of calcium in the blood with low calcium with food.

1.2 Support for the immune system:

Vitamin D plays an important role in the regulation of the immune system. It affects the activity of various immune cells, including T cells, B cells and macrophages. Vitamin D deficiency is associated with increased susceptibility to infections, autoimmune diseases and some types of cancer.

  • Regulation of T cells: Vitamin D affects the differentiation and function of T cells that play a key role in cellular immunity. It can contribute to the transition of T cells from a state of naivety to a state of activation, as well as influence the balance between different T-cell subtypes, such as Th1, Th2 and Th17.

  • Regulation of V-cells: Vitamin D affects the differentiation and products of antibodies with in-cells that provide humoral immunity. It can contribute to the ripening of B cells and an increase in the products of immunoglobulins.

  • Macrophage Regulation: Vitamin D affects the activity of macrophages that phagocytizing pathogens and secreting cytokines. It can contribute to the activation of macrophages and strengthen their antimicrobial activity.

  • Influence on inflammation: Vitamin D has anti -inflammatory properties. It can suppress the products of pro -inflammatory cytokines and strengthen the products of anti -inflammatory cytokines. This can be useful in the treatment of autoimmune diseases and other inflammatory conditions.

1.3 maintenance of the nervous system:

Vitamin D plays an important role in maintaining the health of the nervous system. It affects the growth and differentiation of neurons, the synthesis of neurotransmitters and the protection of nerve cells from damage. The deficiency of vitamin D is associated with an increased risk of development of depression, Alzheimer’s disease and other neurodegenerative diseases.

  • Influence on the growth and differentiation of neurons: Vitamin D promotes the growth and differentiation of neurons, ensuring the normal development of the brain and nervous system. It can stimulate the formation of new synapses and improve the transmission of nerve impulses.

  • Influence on the synthesis of neurotransmitters: Vitamin D affects the synthesis of neurotransmitters, such as dopamine, serotonin and acetylcholine, playing a key role in the regulation of mood, sleep, memory and other cognitive functions.

  • Protection of nerve cells from damage: Vitamin D has neuroprotective properties. It can protect nerve cells from damage caused by oxidative stress, inflammation and other factors.

1.4 Other functions:

In addition to the above, vitamin D is involved in many other processes in the body, including:

  • Regulation of blood pressure.
  • Maintaining health of the cardiovascular system.
  • Regulation of blood sugar.
  • Maintenance of muscle health.
  • Participation in cellular growth and differentiation processes.

Section 2: Vitamin D: causes, symptoms and consequences

Vitamin D deficiency is a common problem around the world, especially in regions with insufficient sunlight and among people with certain risk factors. It can have serious health consequences, especially in children and older people.

2.1 Causes of vitamin D:

  • Insufficient exposure to sunlight: The main source of vitamin D for most people is its synthesis in the skin under the influence of ultraviolet rays (UVB). Factors limiting the effects of sunlight include:

    • Geographical location (high latitudes).
    • Top of year (winter months).
    • Using sunscreen creams.
    • A long stay in the room.
    • Air pollution.
    • Dark skin (requires more time in the sun to synthesize a sufficient amount of vitamin D).

  • Insufficient consumption of vitamin D with food: Some products, such as oily fish, egg yolks and enriched products, contain vitamin D. However, the content of vitamin D in food is often not enough to maintain the optimal level in the blood, especially with limited effects of sunlight.

  • Vitamin D of absorption of vitamin D: Some diseases and conditions, such as Crohn’s disease, celiac disease, cystic fibrosis and resection of the small intestine, may disrupt the absorption of vitamin D in the intestines.

  • Liver and kidney diseases: The liver and kidneys play a key role in the activation of vitamin D. Diseases of these organs can disrupt the activation process and lead to vitamin D.

  • Obesity: Vitamin D is a fat -soluble vitamin, and in people with obesity it can be sequestered in adipose tissue, which reduces its accessibility for the body.

  • Taking some drugs: Some drugs, such as glucocorticoids, antifungal drugs and drugs for the treatment of HIV infection, can affect vitamin D metabolism and lead to its deficiency.

2.2 Symptoms of vitamin D:

Symptoms of vitamin D deficiency can be non -specific and often ignored. In children, vitamin D deficiency can be manifested by rickets, and in adults – osteomalization. However, many people with vitamin D deficiency may not experience any obvious symptoms.

  • In children:

    • Rickets (softening and deformation of bones).
    • Growth retardation.
    • Muscle weakness.
    • Delay of teething.
    • Irritability.

  • In adults:

    • Osteomination (softening of bones).
    • Bones and muscles.
    • Muscle weakness.
    • Frequent fractures.
    • Fatigue.
    • Depression.
    • Reducing immunity.

2.3 consequences of vitamin D:

Vitamin D deficiency may have serious health consequences, including:

  • Rachite (in children): Rickets-a disease characterized by softening and deformation of bones in children due to insufficient mineralization of bone tissue. This can lead to deformation of the legs (o-shaped or x-shaped legs), curvature of the spine, growth retardation and other problems.

  • Osteomulation (in adults): Osteomulation is a disease characterized by softening of bones in adults due to insufficient bone mineralization. This can lead to pain in the bones and muscles, muscle weakness and increased risk of fractures.

  • Osteoporosis: Vitamin D deficiency increases the risk of osteoporosis – a disease characterized by a decrease in bone density and increased fragility of bones. This increases the risk of fractures, especially in the elderly.

  • Muscle weakness: Vitamin D plays an important role in maintaining strength and muscle function. Vitamin D deficiency can lead to muscle weakness and increased risk of falls.

  • Increased risk of infections: Vitamin D plays an important role in the regulation of the immune system. Vitamin D deficiency is associated with increased susceptibility to infections such as respiratory infections, flu and tuberculosis.

  • Autoimmune diseases: Vitamin D deficiency is associated with an increased risk of developing autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis and type 1 diabetes.

  • Cardiovascular diseases: Some studies show that vitamin D deficiency can be associated with an increased risk of developing cardiovascular diseases such as arterial hypertension, coronary heart disease and stroke.

  • Some types of cancer: Some studies show that vitamin D deficiency can be associated with an increased risk of developing certain types of cancer, such as colon cancer, breast cancer and prostate cancer.

  • Depression: Vitamin D deficiency is associated with an increased risk of depression and other mental disorders.

Section 3: Where to get vitamin D? Sources of vitamin D

There are three main sources of vitamin D: sunlight, food and additives. The choice of the optimal source depends on the individual characteristics, lifestyle and geographical position.

3.1 sunlight:

Sunlight is the main source of vitamin D for most people. Under the influence of ultraviolet rays (UVB) in the skin, the synthesis of vitamin D3 (cholecalciferol) from 7-dehydrocholesterol occurs.

  • Factors affecting the synthesis of vitamin D under the influence of sunlight:

    • Top of year: In the winter months, when the sun is low above the horizon, UVB-rays do not reach the surface of the Earth sufficiently for the synthesis of vitamin D in the skin.

    • Geographical position: In high latitudes UVB rays are weaker than in equatorial regions.

    • Times of Day: The synthesis of vitamin D is most effective in the middle of the day when the sun is at a zenith.

    • Cloudness: Clouds are blocked by UVB rays, reducing the synthesis of vitamin D.

    • Air pollution: Air pollution also blocks UVB ray.

    • Skin color: Dark skin contains more melanin, which absorbs UVB ray, reducing the synthesis of vitamin D. People with dark skin need more time in the sun to synthesize a sufficient amount of vitamin D.

    • Age: With age, the ability of the skin to synthesize vitamin D decreases.

    • Using sunscreen creams: High SPF sun creams block UVB ray, significantly reducing the synthesis of vitamin D.

  • Recommendations for the Sun stay for the synthesis of vitamin D:

    • Staying in the sun for 15-20 minutes a day in the middle of the day (from 10:00 to 15:00) in the summer months, without the use of sunscreen creams, allows you to synthesize a sufficient amount of vitamin D for most people.

    • People with dark skin or those who live in high latitudes may need more time in the sun.

    • It is important to remember the risk of sunburn and use sunscreen creams after sufficient time in the sun to synthesize vitamin D.

3.2 food:

Some products contain vitamin D, although the content of vitamin D in food is often not enough to maintain the optimal level in the blood.

  • Fat fish: Fat fish, such as salmon, tuna, mackerel and herring, is a good source of vitamin D.

  • Egg yolks: Egg yolks contain vitamin D, but in smaller quantities than oily fish.

  • Enriched products: Some products, such as milk, yogurt, juices and cereals, are enriched with vitamin D.

  • Mushrooms: Some types of mushrooms, especially those that are exposed to ultraviolet light, contain vitamin D2 (ergocalciferol).

Vitamin D content table in some products (approximate values):

Product Vitamin D (me) content in 100 g
Salmon (wild) 600-1000
Salmon (grown) 100-250
Tuna (canned in oil) 200-300
Mackerel 400-800
Egg yolk 20-60
Milk (enriched) 100
Yogurt (enriched) 80-100

3.3 Supplements:

Vitamin D additives are an effective way to increase the level of vitamin D in the blood, especially for people who do not get a sufficient amount of vitamin D from sunlight and food.

  • Vitamin D3 (cholecalciferol): Vitamin D3 is a preferred form of vitamin D for additives, as it is better absorbed and more effectively increases the level of vitamin D in the blood than vitamin D2.

  • Vitamin D2 (ergocalciferol): Vitamin D2 is a plant form of vitamin D, which can be less effective than vitamin D3.

  • Dosage: The recommended daily dose of vitamin D varies depending on the age, state of health and level of vitamin D in the blood. Adults are usually recommended to take 600-800 IU vitamin D per day. People with vitamin D deficiency may require a higher dose that the doctor must determine.

  • Safety: Vitamin D is a fat -soluble vitamin, and its excessive consumption can lead to toxicity. It is important not to exceed the recommended daily dose of vitamin D, if this is not prescribed by a doctor.

Section 4: How to determine the level of vitamin D in the body? Blood test

The most reliable way to determine the level of vitamin D in the body is a blood test for 25-hydroxyvitamin d [25(OH)D]. This analysis measures the level of vitamin D, circulating in the blood, and allows you to assess its prosperity, insufficiency or deficiency.

4.1 Interpretation of blood test results:

Level 25 (OH) D is measured in nanograms for milliliter (NG/ml) or nanomoli per liter (nmol/l). Interpretation of blood tests can vary depending on the laboratory and the standards used, but the following classification is usually used:

  • Vitamin D deficiency: Less than 20 ng/ml (50 nmol/l).

  • Vitamin D failure: 20-29 ng/ml (50-75 nmol/l).

  • Sufficient level of vitamin D: 30-100 ng/ml (75-250 nmol/l).

  • Toxicity of vitamin D: More than 100 ng/ml (250 nmol/l).

4.2 to whom it is recommended to take a blood test for vitamin D:

Blood test for vitamin D is recommended for people who:

  • Have symptoms of vitamin D (pain in bones and muscles, muscle weakness, fatigue, depression).
  • There are risk factors for vitamin D (dark skin, obesity, elderly age, liver and kidney disease, violation of nutrient absorption).
  • Take medications that can affect vitamin D.
  • Suffer from osteoporosis or other bones.
  • They plan to start taking vitamin D additives in high doses.

4.3 Preparation for blood test:

A blood test for vitamin D usually does not require special preparation. However, it is recommended to inform the doctor about all the drugs taken and additives, as they can affect the results of the analysis.

4.4 What to do after obtaining the results of blood tests:

After receiving the results of blood tests, you need to consult a doctor. The doctor will evaluate the results of the analysis and determine whether you need vitamin D additives and in what dosage. It can also recommend additional studies to exclude other diseases.

Section 5: Recommendations for taking vitamin D. Dosage and safety

Recommendations for taking vitamin D vary depending on the age, state of health and level of vitamin D in the blood. It is important to consult a doctor to determine the optimal dosage and avoid toxicity.

5.1 Recommended daily doses of vitamin D:

Age group Recommended daily dose (me)
Infants (0-12 months) 400
Children (1-18 years old) 600
Adults (19-70 years old) 600
Adults (older than 70 years) 800
Pregnant and lactating women 600

5.2 Correction of vitamin D:

People with vitamin D deficiency may require a higher dose of vitamin D to quickly increase the level of vitamin D in the blood. The doctor may prescribe a shock dose of vitamin D (for example, 50,000 IU per week for several weeks) or a higher daily dose (for example, 2000-5000 IU per day). After reaching a sufficient level of vitamin D in the blood, the dose is usually reduced to the maintenance.

5.3 Factors affecting the need for vitamin D:

  • Age: With age, the skin ability to synthesize vitamin D decreases, and the need for vitamin D increases.
  • Skin color: Dark skin requires more time being in the sun to synthesize a sufficient amount of vitamin D, and the need for vitamin D increases.
  • Obesity: In people with obesity, vitamin D is sequestered in adipose tissue, which reduces its accessibility for the body, and the need for vitamin D increases.
  • Liver and kidney diseases: Diseases of the liver and kidneys can violate the activation of vitamin D, and the need for vitamin D increases.
  • Violation of the absorption of nutrients: Violation of the absorption of nutrients can reduce vitamin D absorption, and the need for vitamin D increases.
  • Taking some drugs: Some drugs can affect vitamin D metabolism, and the need for vitamin D may change.

5.4 Security of taking vitamin D:

Vitamin D is a fat -soluble vitamin, and its excessive consumption can lead to toxicity. Vitamin D toxicity is rare, but can cause the following symptoms:

  • Nausea.
  • Vomit.
  • Weakness.
  • Constipation.
  • Increased urination.
  • Loss of appetite.
  • Increased blood calcium (hypercalcemia).
  • Calcification of soft tissues (calcium deposition in organs and tissues).
  • Renal failure.

To avoid the toxicity of vitamin D, it is important not to exceed the recommended daily dose of vitamin D, if this is not prescribed by a doctor. People taking high doses of vitamin D are recommended to regularly take a blood test for 25 (OH) D to control the level of vitamin D in the blood.

5.5 Interaction of vitamin D with other substances:

Vitamin D can interact with some drugs and additives. It is important to inform the doctor about all the drugs taken and additives in order to avoid undesirable interactions.

  • Corticosteroids: Corticosteroids can reduce the absorption of calcium and vitamin D, increasing the risk of vitamin D. deficiency.
  • Orlistat: Orlistat (drug for the treatment of obesity) can reduce the absorption of fat -soluble vitamins, including vitamin D.
  • Mineral oil: Mineral oil can reduce the absorption of fat -soluble vitamins, including vitamin D.
  • Tiazide diuretics: Tiazide diuretics can increase the level of calcium in the blood, increasing the risk of hypercalcemia while taking vitamin D.
  • Digoxin: Hypercalcemia caused by excessive consumption of vitamin D can increase the risk of digoxin toxicity (drug for the treatment of heart failure).

Section 6: Vitamin D and Covid-19. Scientific data and recommendations

During the Covid-19 pandemic period, the role of vitamin D was actively discussed in the prevention and treatment of this disease. Some studies have shown that vitamin D deficiency can be associated with an increased risk of infection Covid-19, a more severe course of the disease and increased mortality. However, other studies have not confirmed these results.

6.1 Scientific data on vitamin D and covid-19:

  • Observation studies: Some observation studies have shown that people with a lower level of vitamin D in the blood had an increased risk of infection Covid-19, a more severe course of the disease and increased mortality. However, these studies could not establish a causal relationship between vitamin D and Covid-19 deficiency.

  • Randomized controlled studies (RCTs): RCTs are a more reliable type of research, as they allow you to establish a causal relationship. Some RCTs have shown that taking vitamin D additives can reduce the risk of infection with respiratory infections, including influenza and colds. However, RCTs that studied the influence of vitamin D on the course of the Covid-19 gave conflicting results. Some RCTs showed that the intake of vitamin D does not affect the risk of infection Covid-19, the severity of the disease or mortality. Other RCTs showed that the intake of vitamin D adds can reduce the risk of hospitalization and mortality in people with vitamin D.

6.2 mechanisms through which vitamin D can affect the Covid-19:

  • Strengthening the immune system: Vitamin D plays an important role in the regulation of the immune system, and its deficiency can weaken the immune response to infections. Reception of vitamin D additives can strengthen the immune system and increase resistance to infections, including COVID-19.

  • Anti -inflammatory action: Vitamin D has anti-inflammatory properties and can suppress a cytokine storm-an excessive inflammatory reaction, which can lead to a difficult Covid-19.

  • Regulation of angiotensin -converting enzyme 2 (ACE2): ACE2 is a protein used by the SARS-COV-2 virus to penetrate the cells. Vitamin D can regulate the expression ACE2, which can affect the susceptibility to the COVID-19 and the severity of the disease.

6.3 Recommendations for taking vitamin D during the pandemia Covid-19:

Despite the conflicting research results, many medical organizations recommend maintaining a sufficient level of vitamin D in the blood to strengthen the immune system and reduce the risk of respiratory infections, including Covid-19.

  • Recommended daily dose of vitamin D: Most adults are recommended to take 600-800 IU vitamin D per day. People with vitamin D deficiency may require a higher dose that the doctor must determine.

  • Getting vitamin D from food and sunlight: In addition to taking vitamin D additives, it is important to receive vitamin D from food and sunlight. Eat fatty fish, egg yolks and enriched products. Stay in the sun for 15-20 minutes a day in the middle of the day, without the use of sunscreen creams.

  • Consultation with a doctor: Consult a doctor to determine the optimal dosage of vitamin D and avoid toxicity.

Section 7: Vitamin D for different age groups and conditions

The need for vitamin D varies depending on age and health. Consider the features of the intake of vitamin D for different population groups.

7.1 Vitamin D for babies and children:

Vitamin D plays a key role in the development of bones and the immune system in babies and children. Vitamin D deficiency can lead to rickets, growth retardation and increased susceptibility to infections.

  • Recommendations:

    • All babies on breastfeeding are recommended to give additives of vitamin D at a dose of 400 IU per day, starting from the first days of life. Breast milk usually does not contain enough vitamin D to meet the needs of the baby.
    • Infants on artificial feeding, which receive a sufficient amount of vitamin D from the mixture (make sure that the mixture is enriched with vitamin D), additional additives of vitamin D.
    • For children over 1 year, it is recommended to take 600 IU vitamin D per day, especially in the winter months and if they spend less time in the sun.

7.2 Vitamin D for adolescents:

Adolescence is a period of intensive bone growth, and the need for vitamin D increases. Vitamin D deficiency can lead to a decrease in bone density and increased risk of fractures in the future.

  • Recommendations:

    • Adolescents are recommended to take 600 IU vitamin D per day, especially in the winter months and if they spend little time in the sun.
    • Adolescents with obesity, dark skin or diseases affecting the absorption of vitamin D may require a higher dose of vitamin D, which the doctor must determine.

7.3 Vitamin D for pregnant women and lactating women:

During pregnancy and breastfeeding, the need for vitamin D increases, since vitamin D is necessary for the development of the bones and immune system of the child. Vitamin D deficiency in pregnant women can lead to premature birth, low weight and increased risk of rickets in the child.

  • Recommendations:

    • Pregnant and lactating women are recommended to take 600 IU vitamin D per day.
    • Some pregnant women may need a higher dose of vitamin D, which the doctor should determine. Pass the blood test for vitamin D during pregnancy.

7.4 Vitamin D for the elderly:

With age, the ability of the skin to synthesize vitamin D decreases, and older people are more susceptible to vitamin D deficiency. Vitamin D deficiency in older people can lead to osteoporosis, muscle weakness, increased risk of falls and fractures.

  • Recommendations:

    • Older people are recommended to take 800 IU vitamin D per day.
    • Elderly people living in nursing homes or spending less time in the sun may require a higher dose of vitamin D, which the doctor must determine.

7.5 Vitamin D for osteoporosis:

Vitamin D plays an important role in the treatment and prevention of osteoporosis. It helps to absorb calcium from the intestines and maintain sufficient bone mineralization.

  • Recommendations:

    • People with osteoporosis are recommended to take 800-1000 vitamin D per day, in combination with sufficient calcium consumption.
    • The doctor may prescribe a higher dose of vitamin D depending on the level of vitamin D in the blood and other factors.

7.6 Vitamin D for autoimmune diseases:

Some studies show that vitamin D can play a role in regulating the immune system and reducing the risk of developing autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis and type 1 diabetes.

  • Recommendations:

    • People with autoimmune diseases are recommended to maintain a sufficient level of vitamin D in the blood (30-50 ng/ml).
    • The doctor may prescribe a higher dose of vitamin D depending on the level of vitamin D in the blood and other factors. Do not self -medicate and consult your doctor.

7.7 Vitamin D with cardiovascular diseases:

Some studies show that vitamin D deficiency can be associated with an increased risk of developing cardiovascular diseases such as arterial hypertension, coronary heart disease and stroke.

  • Recommendations:

    • People with cardiovascular diseases are recommended to maintain a sufficient level of vitamin D in the blood (30-50 ng/ml).
    • The doctor may prescribe a higher dose of vitamin D depending on the level of vitamin D in the blood and other factors.

7.8 Vitamin D for diabetes:

Some studies show that vitamin D can play a role in regulating blood sugar and reducing the risk of type 2 diabetes.

  • Recommendations:

    • People with diabetes are recommended to maintain a sufficient level of vitamin D in the blood (30-50 ng/ml).
    • The doctor may prescribe a higher dose of vitamin D depending on the level of vitamin D in the blood and other factors.

Section 8: myths and errors about vitamin D

There are many myths and delusions around Vitamin D. It is important to know the truth about vitamin D in order to make reasonable decisions about your health.

  • Myth 1: All people receive enough vitamin D from sunlight.

    • Reality: Many people do not receive enough vitamin D from sunlight, especially in the winter months, in high latitudes, when using sunscreens and with dark skin.

  • Myth 2: Vitamin D can be obtained in sufficient amounts of food.

    • Reality: The content of vitamin D in food is often not enough to maintain the optimal level in the blood, especially with a limited effect of sunlight.

  • Myth 3: Vitamin D additives are always safe.

    • Reality: Excessive

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